Where's the tranny temp read from on a 4L60E?

I need to know where on the 4L60E the tranny temp is read ... and how it's fed to the gauge in the gauge cluster. I'm a bit tranny-stupid (but am learning) ... so pics or diagrams would be very, very helpful.

Some background:
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In my quest to get tranny temp info for my vehicle (in OEM fashion ... i.e. without plugging something into the computer to get it) I did some reasearch, learned that the 04 GMC Sierra 1500 is supposedly pre-wired for a tranny temp gauge, and also learned that it should be as simple as soldering a stepper motor into the gauge cluster.

So, I get a stepper motor, solder it in using a guide I found on the internet, but can't get a temp reading. (A friend checked out the solder work I did and said it looks good.) Further research shows that in some cases a dealership might have to tell the cluster (or computer) a tranny gauge is present. So, I go to a dealership and the dealership gives me all sorts of excuses why they can't -- first they can't because they didn't put the stepper motor in. I tell them fine, take it out and put one in. Without doing so, next they say that even if they do that because the truck didn't come with a gauge they can't tell the truck one is present .. something about lack of calibrations ... and that I'll hav to call GMC customer service, get calibrations added to my VIN, and only then can they tell the truck one is present.

Fine, I called GMC customer service and I have a ticket open with them. But in the mean time I'm thinking this sounds totally ridiculous and is, perhaps, a simple problem that might be solved elsewhere ... i.e. wherever the temp is normally read from within the tranny.
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So that begs the question ... where on the 4L60E is the tranny temp read. Presumably it's a sensor, somewhere ... that presumably plugs into the OEM harness. Could this be as simple as the sensor being absent? Or perhaps the sensor not being plugged into the harness???

Any updates from GMC customer service on this one [MENTION=50075]SurrealOne[/MENTION]? I am interested in doing this to my truck but was letting you be the guinea pig.:shocked: I have the stepper motor already, I was wondering what you discovered.

Any updates from GMC customer service on this one @SurrealOne? I am interested in doing this to my truck but was letting you be the guinea pig.:shocked: I have the stepper motor already, I was wondering what you discovered.

Click to expand...

Nothing new, yet. GMC Customer service has proven incompetent, so far. I seem to know more about the truck than the people I'm dealing with.